Measuring Carotid Intima-Media Thickness in Young Adults Born Preterm: Comparison of Manual Versus Semi-automated B-Mode Ultrasound

Introduction: Young adults born very preterm have increased cardiovascular risks. While intima-media thickness of the common carotid artery is an early marker of atherosclerosis in adults, the most reliable method of its measurement is not established in this population. The purpose of this study is to compare manual and semi-automated B-mode ultrasound intima-media thickness measurement techniques in adults born very preterm and full-term. Methods: Intima-media thickness was measured in adults 18 to 29 years born very preterm (<30 weeks’ gestation) or full-term (≥37 weeks’ gestation) using B-mode ultrasound. Analyses included intraclass correlation coefficient (ICC) and relationships with prematurity status, age, body mass index, and metabolic and respiratory comorbidities. Results: There were 86 preterm-born participants (58% women) and 85 full-term (56% women), mean age 23 ± 2 years. Intra-observer agreement was better using semi-automated (ICC = 0.89; 95% confidence interval (CI) = [0.86-0.91]) than manual measurement (ICC = 0.73; 95% CI = [0.65-0.79]). Measures obtained using both techniques did not detect any differences according to prematurity status, did not correlate with age, and moderately correlated with body mass index. The semi-automated technique showed higher intima-media thickness values in men vs women and overall gave higher values. Results obtained through both techniques moderately correlated with each other when looking at subgroups: preterm group ICC of 0.53, full-term group ICC of 0.62. Conclusion: Manual and semi-automated intima-media thickness measurements moderately correlate in young adults. The semi-automated technique is more reproducible. Both techniques are useful in discriminating intima-media thickness according to weight. This study identifies variance of results according to different techniques of measurements. Adherence to a single technique is recommended in young adults born prematurely. Clinical implication includes adherence to the same technique for risk stratification and for follow-up of these patients.